US4145664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio signal compression and expansion system
Assignee: Pioneer Corp
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Filing: 1978-03-31
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Granted: 1979-03-20
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Expires: 1998-03-31
Abstract
Abstract The auxilliary signal path in a compander system includes, in series, a first amplifier 7, a weighting function amplifier 8, and a detection circuit 9. The output of the latter controls the gain of a voltage-controlled variable gain circuit 11 also connected to the first amplifier output, and the integrated output of the variable gain circuit is fed back to the input of the first amplifier via a subtraction circuit 13 also supplied with the auxilliary signal path input. Alternatively, the first amplifier may comprise an operational amplifier, in which case the integrated signal is directly coupled to one of its inputs.
Inventors
- 👤 Saburo Takaoka
- 👤 Fumihiko Yokogawa
- 👤 Tadahiro Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:17
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/62; H04B1/64; H03; H03G; H03G9/00; H03G9/02; H03G9/025
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
126 words
In a signal compression and expansion system having a main signal path and an auxiliary signal path connectable therewith in a feedback or feedforward mode, said auxiliary signal path including amplifier means (7); a weighting function amplifier (8) connected to the output of said amplifier means; and a detection circuit (9) connected to the output of said weighting function amplifier; the improvements characterized by: (a) a voltage-controlled variable gain circuit (11) for amplifying the output of said amplifier means; (b) means connecting the output of said detection circuit to a gain-control input of said variable gain circuit; (c) means (12) for integrating the output of said variable gain circuit; and (d) means (13) for feeding back said integrated output to the input of said amplifier means.
Claim 2
Dependent Claim
126 words
In a signal compression and expansion system having a main signal path and an auxiliary signal path connectable therewith in a feedback or feedforward mode, said auxiliary signal path including amplifier means (7); a weighting function amplifier (8) connected to the output of said amplifier means; and a detection circuit (9) connected to the output of said weighting function amplifier; the improvements characterized by: (a) a voltage-controlled variable gain circuit (11) for amplifying the output of said amplifier means; (b) means connecting the output of said detection circuit to a gain-control input of said variable gain circuit; (c) means (12) for integrating the output of said variable gain circuit; and (d) means (13) for feeding back said integrated output to the input of said amplifier means.
Claim 3
Dependent Claim
42 words
A system as claimed in claim 1, wherein said feeding back means comprises a subtraction circuit for applying the difference between the output of said integrating means and the input of said auxiliary signal path to the input of said amplifier means.
Claim 4
Dependent Claim
31 words
A system as claimed in claim 1, wherein said amplifier means comprises an operational amplifier, and the output of said integrating means is one of two inputs of said operational amplifier.
References Cited (Backward Citations)
US3729693A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-19 | 1982-09-18 | 1983-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-19 | 1986-09-18 | 1987-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-19 | 1990-09-18 | 1991-03-20 | $7700.00 | Window Closed / Lapsed |